hphp/hack/manual/apis/Classes/HH/ImmMap/lazy.md
:::info[Note] This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information. :::
Returns a lazy, access elements only when needed view of the current
ImmMap
public function lazy(): KeyedIterable<Tk, Tv>;
Normally, memory is allocated for all of the elements of an ImmMap. With
a lazy view, memory is allocated for an element only when needed or used
in a calculation like in map() or filter().
KeyedIterable<Tk,Tv> - a KeyedIterable representing the lazy view into the current
ImmMap.See Map::lazy for usage examples.